CONTROL OF GARDEN DISEASES AND INSECTS. 



47 



and it may continue to attack plants throughout the season. The 

 disease is caused by bacteria Avhich grow in the water vessels of the 

 plant, thus cutting off its water supply. As the disease is carried 

 largely by the striped cucumber beetle, the plants should be kept 

 covered as long as possible with insect-proof cages (see " Striped 

 cucumber beetle," p. 43) or sprayed with lead arsenate, one-half 

 lH)und dry to 10 gallons of water, to kill the beetles. Diseased plants 

 should be pulled promptly and burned or buried. 



ANTHKACNOSE. 



Anthracnose (fig. 52) is a disease affecting principally the leaves 

 and stems of the plant. It causes brown spots, one-fourth to one-half 

 inch in diameter, on the leaves, which when numerous kill them. The 

 oldest leaves in the center of the plant are attacked first, about the 

 latter part of July in the latitude of northern Ohio. With warm, 

 moist Aveather the disease spreads rapidly^ and the plants are often 

 completely killed before the end of the season. Thorough spraying 

 with Bordeaux mix- 

 ture will hold the ^^ "^ ^ 

 disease in check but 

 will not entirely 

 control it. Cucum- 

 bers s^houlcl not be 

 planted in the same 

 place in succeeding 

 years. This disease 

 and the next may be 

 spread by infected 

 seed. 



ANGULAR LEAF-SPOT. 



Angular leaf -spot 

 attacks the leaves in 

 late July, causing 

 angular spots one- 

 sixteenth to one- 

 eighth of an inch 

 across, first water soaked, later sometimes whitened, and during 

 continued wet weather it may cause considerable damage. It can 

 be controlled largely by spraying with Bordeaux mixture. 



MOSAIC DISEASE. 



The mosaic disease, sometimes called " Avhite pickle," occurs 

 throughout the Middle West and causes mottling of the leaves 

 (fig. 53), warting of the fruits (fig. 54), stunting and yellowing 

 of the plants, and great reduction of the yield. The cause of 



-Cucumber leaf, showing mosaic disease. 



